﻿using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;

using System.Diagnostics;




public partial class Account_MyCheckCode : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        this.CreateCheckCodeImage(GenerateCheckCode());
    }





    #region  生成 验证码的部分.



    /// <summary>
    /// 排除容易混淆的 0 与 O,  1 与 I,  8 与 B
    /// </summary>
    private static readonly char[] CodeArray = {'2', '3', '4', '5', '6', '7', '9',
												'A', 'C', 'D', 'E', 'F', 'G', 'H', 'J',
												'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U',
												'V', 'W', 'X', 'Y', 'Z'};


    /// <summary>
    /// 产生验证码.
    /// </summary>
    /// <returns></returns>
    private string GenerateCheckCode()
    {
        int number;
        char code;
        string checkCode = String.Empty;

        System.Random random = new Random();

        for (int i = 0; i < 5; i++)
        {
            number = random.Next();



            //if (number % 2 == 0)
            //    code = (char)('0' + (char)(number % 10));
            //else
            //    code = (char)('A' + (char)(number % 26));

            code = CodeArray[(number % CodeArray.Length)];

            checkCode += code.ToString();
        }


        // Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));

        Session["CheckCode"] = checkCode;

        return checkCode;
    }


    #endregion




    #region  生成图片的部分.



    /// <summary>
    /// 验证码随机使用的字体.
    /// </summary>
    private static Font[] codeFontArray = new Font[] {
            new System.Drawing.Font("MV Boli",11,(System.Drawing.FontStyle.Italic)),
            new System.Drawing.Font("Vijaya",14,(System.Drawing.FontStyle.Bold)),
            new System.Drawing.Font("Vrinda",12,(System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic)),
        };



    /// <summary>
    /// 生成图片.
    /// </summary>
    /// <param name="checkCode"></param>
    private void CreateCheckCodeImage(string checkCode)
    {
        if (checkCode == null || checkCode.Trim() == String.Empty)
            return;

        // 定义图片大小.
        System.Drawing.Bitmap image =
            new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 14.5)), 26);

        Graphics g = Graphics.FromImage(image);


        try
        {
            // 生成随机生成器
            Random random = new Random();

            // 清空图片背景色
            g.Clear(Color.White);

            // 画图片的背景噪音线
            for (int i = 0; i < 25; i++)
            {
                int x1 = random.Next(image.Width);
                int x2 = random.Next(image.Width);
                int y1 = random.Next(image.Height);
                int y2 = random.Next(image.Height);

                g.DrawLine(new Pen(Color.GreenYellow), x1, y1, x2, y2);
            }

            Font font = new System.Drawing.Font(
                "Verdana",
                12,
                (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));


            System.Drawing.Drawing2D.LinearGradientBrush brush =
                new System.Drawing.Drawing2D.LinearGradientBrush(
                    new Rectangle(0, 0, image.Width, image.Height),
                        Color.Blue, Color.DarkRed, 1.2f, true);


            // g.DrawString(checkCode, font, brush, 2, 2);

            for (int i = 0; i < checkCode.Length; i++)
            {
                g.DrawString(
                    checkCode[i].ToString(),
                    codeFontArray[random.Next() % codeFontArray.Length],
                    brush,
                    2 + (12 * i),
                    2);
            }


            // 画图片的前景噪音点.
            for (int i = 0; i < 80; i++)
            {
                int x = random.Next(image.Width);
                int y = random.Next(image.Height);

                image.SetPixel(x, y, Color.FromArgb(random.Next()));
            }

            // 画图片的边框线
            g.DrawRectangle(new Pen(Color.Red), 0, 0, image.Width - 1, image.Height - 1);


            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            Response.ClearContent();
            Response.ContentType = "image/Gif";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            g.Dispose();
            image.Dispose();
        }
    }


    #endregion

}